Lightning and Trees

Subscriber-only episode

In this Wednesday episode of Talking Trees, we investigate the powerful and often underestimated role of lightning in the life and death of trees. Lightning not only causes physical damage but may also shape tree evolution and biodiversity over time.

We explore:

• How lightning strikes affect tree aging, decay processes, and habitat creation
• The ecological significance of lightning-damaged trees as microhabitats for biodiversity
• Current technical standards for lightning protection, including components, installation procedures, and long-term maintenance
• When and why to install lightning protection systems in high-value or ecologically important trees
• Insights from arboricultural and engineering practices that help reduce tree loss due to strikes

Lightning is not just a destructive force—it’s a natural phenomenon deeply intertwined with forest dynamics and arboricultural care.

Background information:

• 2003 - The possible role of lightning in the tree evolution and biodiversity - Fay.pdf
• KnŪöka 2.1 Final.pdf
• SPPK A02 006_2015Ochrana_Blesk_FINAL_AOPK.pdf

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Chapters

• 0:00 Introduction to Lightning Protection
• 2:35 The Power and Impact of Lightning
• 6:40 Tree Species Vulnerability
• 8:33 Czech Standard Protection Systems
• 12:17 Designing Lightning Resilient Spaces
• 14:10 Key Assessment Factors

Transcript

Roger: 0:02

Talking Trees with Lillian Jad. Welcome to Talking Trees. Today we explore lightning protection from two perspectives. One set of texts examines the ecological impact of lightning on trees, its role in evolution and biodiversity, while the other provides practical guidelines for safeguarding buildings and infrastructure from lightning strikes and surges. We'll also touch on Czech national standards, which outline technical requirements for protecting trees and their surroundings.

Jad: 0:38

You know, as arborists, we're always thinking about tree health and how to keep those trees thriving right.

Lilly: 0:43

Absolutely.

Jad: 0:44

But today we're going to look at something that can cause some serious damage in the blink of an eye.

Lilly: 0:47

Oh yeah.

Jad: 0:48

Lightning.

Lilly: 0:49

It's a powerful force of nature.

Jad: 0:51

It is, and we're diving deep into how powerful it really is, what that means for the trees that we're caring for Right. And then we're going to explore some fascinating protection strategies coming straight from the Czech standard on lightning protection systems.

Lilly: 1:07

That Czech standard is a great resource, really interesting stuff.

Jad: 1:11

It is so to kick things off.

Lilly: 1:13

Yeah.

Jad: 1:14

Can you give us a sense of the sheer power of lightning? What are we talking about here in terms of energy?

Lilly: 1:19

Well, you know, we see lightning, but sometimes it's hard to really grasp just how powerful it is.

Roger: 1:25

Yeah.

Lilly: 1:25

We're talking millions of volts, megawatts of energy. It's like the sudden release of energy that we rarely see on that scale anywhere else in nature.

Jad: 1:35

Yeah, that's a lot of energy and that translates to some very real consequences for trees. I mean, we've all seen it. You know trees that have been struck by lightning bark stripped away, branches scorched.

Lilly: 1:45

Oh yeah.

Jad: 1:45

It's a powerful reminder of nature's power.

Lilly: 1:48

For sure, but you know, it's not always that dramatic.

Jad: 1:51

Right.

Lilly: 1:51

Lightning can actually travel through a tree in a few different ways. Correct. Sometimes it'll go over the bark down to the roots, and that kind of damage can be harder to spot right away.

Jad: 2:00

Oh interesting. Other times it discharges through the cambial zone and that leaves those telltale scars and furrows that you might be familiar with. And as arborists, we know that cambial damage is a serious issue. It can really impact a tree's stability and its overall health.

Lilly: 2:17

Yeah, exactly, it's not just the immediate damage that you see. You've got to think about what's going on inside the tree too.

Jad: 2:22

So it's like a hidden threat almost.

Lilly: 2:23

In a way, yeah, and to make things even more complicated, the path that lightning takes through a tree can be really unpredictable.

Jad: 2:31

Oh really.

Lilly: 2:31

It's not always a straight line right through the middle.

Jad: 2:34

Interesting.

Lilly: 2:38

And that makes it hard to know just how bad the damage is. You know, in one case you might see a little bit of bark stripping.

Jad: 2:45

And in another you might have the whole tree just destroyed. So, as we're out there assessing trees, what are some of the things that we should be looking for to determine if lightning might have been a factor?

Lilly: 2:53

Well, one thing to keep in mind is that crown dieback can happen after a lightning strike.

Jad: 2:57

Okay.

Lilly: 2:58

And it looks a lot like the natural aging process.

Jad: 3:01

So it can be tricky to tell the difference.

Lilly: 3:03

Yeah, it can. And this accelerated aging because of the stress from the lightning and, you know, not all trees are equally susceptible to lightning strikes.

Jad: 3:11

That's right. Are there certain species that we should be paying closer attention to?

Lilly: 3:17

There are oaks, ashes, elms. These species tend to be more vulnerable, while others, like beeches and birches, seem to fare a bit better.

Jad: 3:27

I wonder, why that is.

Lilly: 3:29

You know, there's some research that suggests it might have something to do with the chemical composition of the wood. Oh, interesting. Whether they're starch-rich or oil-rich.

Jad: 3:37

Huh, never thought about that. The chemistry of a tree playing a role in its lightning susceptibility.

Lilly: 3:41

Yeah, it's amazing what you learn when you start looking into these things.

Jad: 3:45

It is. And just to really highlight how common lightning strikes are, I came across some research by Neville Fay.

Lilly: 3:52

Oh yeah, Neville Fay, he's a great arborist.

Jad: 3:54

He surveyed over 800 oak trees and found that 13% of them showed evidence of a past lightning strike 13%.

Lilly: 4:03

That's a significant number.

Jad: 4:04

Yeah, it really is. So, knowing that lightning is a real threat, how do we go about protecting the trees that we're caring for?

Lilly: 4:10

Well, that's where this check standard comes in, right, and it outlines two main levels of protection LPL2 and LPLV.

Jad: 4:16

Okay, and what's the difference between those two?

Lilly: 4:18

LPL2,. That's a higher level of protection, usually for really important trees like historically significant trees or trees in exposed locations.

Jad: 4:25

I see.

Lilly: 4:26

And then LPL fee is more of a standard level of protection for most situations.

Jad: 4:29

Okay, so what does an actual lighting protection system? What do they look like? What are the key parts?

Lilly: 4:36

Well, you've got three main components the catching system, the down conductor system and the grounding system.

Jad: 4:43

Okay, let's break those down one by one, starting with the catching system. What's its main job?

Lilly: 4:48

Well, as the name suggests, it's designed to catch the lightning bolt before it hits the tree.

Jad: 4:53

Makes sense.

Lilly: 4:54

And typically it involves a catching rod that's placed higher than the crown of the tree.

Jad: 4:58

So you're basically giving the lightning a more attractive target than the tree itself.

Lilly: 5:02

Exactly, and the way this catching system is set up can vary depending on the shape of the tree's crown.

Jad: 5:07

Oh right, Because trees come in all shapes and sizes.

Lilly: 5:10

They do conical, spherical, umbrella-like. There are guidelines for each one. It's all about tailoring it to the specific tree. Guidelines for each one.

Jad: 5:18

It's all about tailoring it to the specific tree I like it. So once the lightning is caught by this rod, how does it get safely down to the ground?

Lilly: 5:23

Well, that's where the down conductor system comes in. It's basically a network of conductors that carry the lightning current down the trunk to the ground.

Jad: 5:31

And I'm guessing placement of these conductors is pretty important.

Lilly: 5:34

It's crucial. You don't want to cause more damage to the tree while you're trying to protect it Right, so they're usually run along the main branches and the trunk.

Jad: 5:41

Makes sense.

Lilly: 5:42

And in some cases they can even be allowed to grow into the tree.

Jad: 5:45

Oh wow, so it becomes part of the tree itself.

Lilly: 5:48

It does. It's pretty amazing.

Jad: 5:49

Yeah, that's a really cool detail. So we've got to get all that energy safely into the ground. Exactly. And it's got to be done right to make sure that energy flows efficiently and doesn't cause any harm. I imagine soil conditions probably play a big role in how effective the grounding is.

Lilly: 6:11

You're absolutely right. The type of soil and how deep you go with the grounding system, those are critical factors.

Jad: 6:18

Okay.

Lilly: 6:18

Sandy soil versus clay soil. Those are going to require different approaches.

Jad: 6:23

So it's not just about knowing trees, it's about knowing the ground too.

Lilly: 6:26

It's about understanding the whole picture.

Jad: 6:29

And this check standard seems to really emphasize that holistic view.

Lilly: 6:34

It does. One of the things I really appreciate about it is the level of detail.

Jad: 6:38

Oh yeah.

Lilly: 6:39

They go as far as specifying the exact materials and even the minimum size for the conductors, the grounding rods, all of it.

Jad: 6:46

Wow, so they've really thought of everything.

Lilly: 6:48

They really have, and that level of detail makes a big difference in how well the system works.

Jad: 6:52

But even with the best system in place, regular maintenance is still key right.

Lilly: 6:58

Absolutely. You can't just install it and forget about it.

Jad: 7:00

That's why things change. Trees grow.

Lilly: 7:01

Exactly so. The check standard really emphasizes the importance of those regular inspections and keeping up with maintenance.

Jad: 7:08

So visual checks making sure everything is still in good working order.

Lilly: 7:12

Exactly, and you know it's not just about checking the hardware Right. You got to assess the tree itself too, of course. Has it grown a lot? Are there new branches that might need protection? It's an ongoing process.

Jad: 7:25

I'm wondering could we apply these principles to create something like a lightning resilient forest or even a more resilient urban green space?

Lilly: 7:34

That's a really interesting thought and, you know, with climate change potentially leading to more frequent and intense thunderstorms, it's something we should definitely be thinking about.

Jad: 7:42

That's a good point.

Lilly: 7:43

Yeah.

Jad: 7:43

And we know that some tree species are more vulnerable to lightning than others. So if we're planning these urban green spaces or working on reforestation projects, wouldn't it make sense to prioritize those more resilient species?

Lilly: 7:56

Absolutely, and it's not just about which species we choose. We can also think about the design and layout of these spaces.

Jad: 8:02

Oh, how so.

Lilly: 8:02

Well imagine incorporating natural learning protection features like taller trees strategically placed to act as natural lightning rods, or even using water features to help dissipate the energy from a strike.

Jad: 8:15

That's a really intriguing idea. It's like designing with lightning in mind rather than just reacting to it after the fact.

Lilly: 8:22

Exactly. It's about taking a proactive approach to mitigating the risks this idea of shifting our whole paradigm of tree care.

Jad: 8:31

Instead of just focusing on the individual tree, we need to start thinking about the entire ecosystem and how we can build resilience into the landscape itself.

Lilly: 8:39

I couldn't agree more. It's about seeing the bigger picture.

Jad: 8:42

So, thinking about the check standards approach to protecting individual trees, what are some practical takeaways that our fellow arborists can use when assessing a tree for potential lightning protection? What should we be looking for?

Lilly: 8:56

Well, it all starts with a comprehensive risk assessment and, as you know from your experience, certain species are more susceptible to lightning strikes. Oaks, ashes, elms, those are some that come to mind right away.

Jad: 9:08

Right, and we talked about how location plays a role too.

Lilly: 9:11

Absolutely. A tree on a hilltop or near water. It's going to be more exposed and at a higher risk. Right, and you also want to consider the surroundings Are there taller structures nearby that could potentially act as lightning rods?

Jad: 9:23

Good point.

Lilly: 9:23

And of course, you always want to assess the overall health and structural integrity of the tree.

Jad: 9:28

Right. A tree that's already weakened or compromised is going to be more vulnerable.

Lilly: 9:31

Exactly.

Jad: 9:32

So it's a multifaceted evaluation species location, overall health, all important factors and I'm thinking having a good understanding of the site history is helpful too.

Lilly: 9:42

Oh, absolutely. Has this tree or trees in this area been struck before? Knowing the history can give you valuable insights.

Jad: 9:49

It's like having a built-in early warning system.

Lilly: 9:52

Exactly.

Jad: 9:52

So let's revisit those components one by one, starting with the catching system. What are the key considerations for placing that catching rod for optimal effectiveness?

Lilly: 10:02

Well, height is crucial. The rod needs to be the highest point. The most attractive target for the lightning Makes sense.

Lilly: 10:16

And, as the standard emphasizes, the configuration of that catching system needs to be tailored to the shape of the tree's crown. Right, because trees come in all shapes and sizes. They do. A single rod might be enough for a tall conical crown, but a broader spreading crown might require multiple rods or even a cable system. And then we move on to the down conductor system, that network of conductors that channel the current down the tree. Placement here is essential to avoid damaging the tree while making sure the current flows efficiently.

Jad: 10:40

And I imagine selecting the right type of conductor and carefully planning its route is really important here.

Lilly: 10:46

It is, and the check standard provides specific guidance on this, even down to the materials, the minimal sizes and how fasteners should be placed to minimize damage to the bark and cambium.

Jad: 10:58

It's really impressive how much detail they put into this.

Lilly: 11:00

They've really thought of everything.

Jad: 11:02

And that makes sense given the amount of energy we're dealing with. Exactly Now, let's talk about the grounding system, the foundation of it all. What are the essential aspects we need to get right here?

Lilly: 11:11

The goal is to create a low-resistance pathway for that electrical current to flow into the earth. Okay, so that means choosing the right grounding rod material, driving it deep enough and critically understanding the soil conditions. So, a sandy soil versus a clay soil, for instance, would require different grounding strategies. Absolutely, soil conductivity is a huge factor and, again, the Czech standard provides detailed guidelines for calculating the depth and configuration of the grounding system based on those specific soil types.

Jad: 11:41

It really highlights the importance of understanding the whole picture, not just the tree in isolation, but the ground it grows in as well.

Lilly: 11:47

Exactly, it's all connected.

Jad: 11:49

It is, and even with a perfectly designed and installed system, regular maintenance is still key right. What are some red flags we should be looking for during those inspections?

Lilly: 11:59

You're absolutely right. Ongoing maintenance is critical. During your inspections, keep an eye on the condition of those conductors. Look for any signs of corrosion, damage loose connections. Make sure the grounding system is still secure and hasn't been affected by things like soil erosion or root growth.

Jad: 12:15

So it's about being proactive and catching those potential issues before they become big problems.

Lilly: 12:20

Exactly, and don't forget to look at the tree itself. Has it grown significantly since the system was installed? Are there new branches that might now extend beyond the zone of protection?

Jad: 12:32

Right. It highlights the importance of continuous observation and understanding how trees change over time.

Lilly: 12:38

Precisely, lightning protection isn't a set-it-and-forget-it kind of deal. It's an ongoing commitment to the health and longevity of these incredible trees.

Jad: 12:47

And speaking of incredible trees, we touched earlier on the idea of creating lightning resilient landscapes. We know that some species are more susceptible to lightning than others, so could that play a role in how we approach planting, especially in urban areas, or reforestation projects?

Lilly: 13:04

Absolutely. If we're planting in areas that are prone to lightning strikes, prioritizing species that are naturally more resistant just makes good sense. It's a simple yet powerful strategy for building resilience into the landscape from the very beginning.

Jad: 13:16

Well, this has been a fascinating conversation. I've learned so much about lightning protection and the Czech standard.

Lilly: 13:21

It's a great resource.

Jad: 13:22

It is. So, as we wrap up today, what's the one key takeaway that you'd like our fellow arborists to leave with?

Lilly: 13:30

If I had to pick just one, it would be this knowledge is power. When it comes to lightning protection, the more we understand about how lightning works, what makes trees vulnerable and the strategies we can use to protect them, the better decisions we'll be able to make for the trees that we care for.

Jad: 13:47

I couldn't agree more. It's about anticipating the risks and taking steps to mitigate them.

Lilly: 13:52

And the Czech standard gives us a great roadmap for doing just that.

Jad: 13:55

It does. It's an invaluable resource for any arborist who's serious about protecting trees from lightning.

Lilly: 14:00

Absolutely.

Jad: 14:01

Well, it's been a pleasure talking with you today.

Lilly: 14:03

Likewise.

Jad: 14:04

And to our listeners out there keep those trees healthy and thriving and until next time, happy treeing.

Lilly: 14:11

Happy treeing.

Roger: 14:16

Thank you for joining us Today. We discussed lightning protection from dual perspectives, its ecological impact on trees and the practical guidelines for safeguarding buildings and infrastructure, including Czech national standards. We appreciate your attention and look forward to our next discussion.